Utility storage customers who deploy thin provisioning and related thin copy technologies require just one terabyte of capacity for every 2.5 terabytes required with traditional storage arrays. Because these thin technologies employ a high degree of virtualisation and automation, they dramatically reduce storage administration time and effort—for example, by eliminating common storage provisioning tasks. This substantial reduction in capacity and administrative burden can produce massive cost savings: UK firm SAVVIS even claims that utility storage has enabled them to cut storage administration and operational costs by an astonishing 50% (http://www.3par.com/news/_pr/072705.shtml).
Not only do these capacity and energy savings produce very tangible cost savings, but they also translate into a reduction in the environmental impact of storage. In fact, by reducing disk capacity requirements and increasing energy efficiency, thin technologies can reduce the carbon footprint associated with storage by approximately 60% (http://www.3par.com/news/_pr/041807.shtml). As a result, thin technologies originally developed to increase storage efficiency are now being touted as a more environmentally responsible alternative to traditional storage. But how do thin technologies such as thin provisioning achieve these incredible benefits?
Thin Technologies: A Radical New Approach
Thin provisioning achieves such dramatic benefits by taking a radical new approach—applying a timelessly simple idea to a new problem: the concept of “pooling” previously “silo’d” resources in order to better meet the individual needs of the collective whole. In this respect, thin provisioning could easily be compared to the municipal irrigation systems first developed by the Romans. In Roman times, instead of each household having to maintain its own well, this was taken care of by a municipal infrastructure—similar to the one we still use today. This infrastructure takes care of identifying safe water sources, preparing that water for consumption, and then transporting and storing potable water in holding tanks or reservoirs. Though truly an amazing feat of engineering, today this entire system works so well that we hardly need to think about it; all we need to do is turn a tap!
Not only is this infrastructure elegant in its simplicity, but it gives each of us the benefits of pooling our individual resources. A single reservoir may contain many times more water than any individual family needs, yet by connecting multiple households to this shared pool we are able to maximise the number of people serviced by a single water source. There is no need to maintain a large surplus of water in the pool, even when serving a large number of households, since more water can simply be pumped in at the point that the reservoir begins to run low.
Thin provisioning and other thin technologies use this concept of pooling all storage system capacity into a common “reservoir” that is shared by all storage system applications. With thin provisioning, separate storage reserves for each volume or application are not required—a common storage reservoir of moderate size will do to start. Applications draw capacity from that reservoir only as needed. More storage can be added to the pool as more applications draw from it, or as their needs grow. Only as applications write data is actual physical capacity committed—as if drawing water from the reservoir. Therefore, a large up-front reserve is simply not necessary, yet all applications benefit from sharing the pooled resources.
As simple as it is, this model is radically different from the approach taken by traditional storage arrays, which require storage to be allocated to each individual application up-front. With these traditional arrays, once up-front capacity is allocated to an application, it is locked away from use, regardless of whether or not it is ever really required. Needless to say, this can lead to a great deal of allocated but unused—in other words, wasted—capacity. In fact, overallocation and underutilisation are two major issues plaguing traditional storage arrays.
By contrast, with thin provisioning, the dedication of physical capacity from the shared reservoir is made only on an as-needed basis, almost completely eliminating waste. In fact, this dedicate-on-write approach drives up the ratio of utilisation efficiency to nearly 100%.
Traditional Provisioning Versus Thin Provisioning
Physical capacity is purchased to meet today’s actual demands rather than projected demands. This method is extremely flexible since capacity can always be added to the thin provisioning reservoir and applications can always draw more capacity as needed.
Simply put, thin technologies such as thin provisioning enable organisations to purchase only what they use and use only what they need. This amazingly simple concept breaks the traditional linkage between allocated and purchased capacity. It does this through the use of storage virtualisation techniques, which have sparked a paradigm shift that is changing how many organisations view storage. “It is becoming increasingly important for IT departments to deploy just the right amount of capacity over time and provision capacity according to the exact needs of the business,” said Claus Egge, IDC’s European Program Director for storage research.
Thinking Thin to Think Green
But how does thin provisioning translate to such massive energy savings? By driving up utilisation rates, thin provisioning and thin technologies deliver more with less—fewer disks, fewer kilowatt hours, fewer carbon emissions. In today’s world, not only do we have more data to store, but rising fuel costs mean that storing this mushrooming amount of data is now more expensive than ever. But perhaps the impact to the environment is the highest price tag of all. The disk drives spinning in data centres around the world today are responsible for the equivalent emissions of 9 million cars on an annual basis. The environmental impact of data centre storage can no longer be ignored.
Thin provisioning is a technology that has already been widely touted because it enables customers to support their storage needs with only a fraction of the physical storage required by traditional arrays. Now that thin technologies are doing more than just reducing the cost of capacity, power and cooling, they are poised to become even more significant. For example, earlier this year 3PAR announced that their Utility Storage customers alone are responsible for an estimated worldwide combined annualised energy savings of approximately $6.6 million (http://www.3par.com/news/_pr/041807.shtml). This savings is equivalent to eliminating approximately 48,000 metric tons of CO2 and 250,000 kilowatt-hours of electricity.
With thin provisioning and thin copy technologies, customers not only save significantly on energy costs associated with power and cooling the storage environment, but they are also doing something to help our planet, thus pioneering the green storage revolution—whether they know it or not.
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